Chorionic villus sampling (CVS)
- CVS is a prenatal diagnostic test.
- It is only offered to some women during pregnancy.
- CVS is done to confirm if a baby has a genetic condition.
What is CVS?
Chorionic villus sampling (CVS) is a diagnostic test done after 11 weeks of pregnancy to confirm if your baby has a genetic disorders or other chromosome condition. This test is not offered to all pregnant women. CVS may help in making important decisions about your pregnancy. While some women are advised to have this procedure the final decision to do so is yours.
Is CVS right for me?
Your doctor may recommend CVS if:
- you have had a high risk prenatal screening test result
- you have already had a child with a genetic or chromosomal condition
- you are 35-37 years of age or over when your baby is due
- if both parents are carriers of a particular condition
- you would like greater certainty about a diagnosis of Down syndrome or some other genetic condition
Before you have the test it’s a good idea to think about why you are choosing to do it, and how you will feel once you get the results. Consider also who you want to discuss any important decisions with — your partner, a friend or family member, or a health professional such as your doctor or midwife are all good options.
Can CVS harm my baby?
There is a small risk of miscarriage with every pregnancy, CVS can slightly increase that overall risk.
The risk of miscarriage associated with CVS is estimated to be between 1 in 100 pregnancies, although could be as low as 1 in 500 pregnancies according to recent research.
How is the CVS performed?
CVS is performed by a specialist doctor in a hospital or specialist women’s ultrasound service.
The procedure involves inserting a very thin needle into the placenta through your abdomen (known as a ‘transabdominal’ procedure) to take a very small sample of cells from your placenta.
The doctor will use an ultrasound to guide the needle, avoiding contact with your baby. The procedure itself only takes a few minutes.
Your doctor will tell you if you need to do anything before the procedure, in some cases, you may need to have a full bladder. You will be given local anaesthetic to numb the skin before the needle is inserted and will be awake for the procedure.
Sometimes if the placenta cannot be reached from a needle through the abdomen, a CVS can be done by inserting a needle through the vagina and cervix (known as a ‘transcervical’ procedure).
Depending on your individual circumstance, your doctor may ask to delay testing until you are 15 weeks pregnant when you can have an amniocentesis.
Who performs the CVS procedure?
Your doctor or midwife will refer you to a specialist obstetrician or obstetric imagining specialist.
You can use the Service Finder to find a specialist obstetrician near you. However, you will need a referral from your healthcare provider for this procedure.
How will I feel after the procedure?
Most women only experience minor discomfort, cramping and period like pain, during and after CVS. The procedure itself takes a few minutes, but you will most likely be asked to sit and rest in a waiting area for around 30 minutes after the procedure before you can go home.
If you have a negative blood group, an Anti-D injection would be given after the procedure.
You might experience some mild period-like pain on the first night after the procedure, it is safe to use regular paracetamol if you need it.
If you have any vaginal bleeding, severe abdominal pain, high fever or unusual discharge from your vagina in the first couple of days or weeks after the procedure, you should go to your nearest hospital emergency department.
When do I get the results of my CVS?
Depending on your individual circumstance and the tests requested by the doctor performing the procedure, results of a CVS may be available in 1-2 working days, or up to 2 weeks. You can confirm when you will receive these results with your doctor.
How much does CVS cost?
Medicare will cover a proportion of the cost of the CVS procedure, but there may be some other costs involved: for example, if you have a private obstetrician, there may be consultation fees for the procedure. Ask your doctor for more information about the costs involved in your specific circumstances.
Questions you might want to ask your doctor
Here are some questions you might want to ask your midwife or doctor:
- Why are you offering me this test?
- What does the procedure involve, do I need to do anything on the day?
- When will I get the results?
- Who will contact me to give me the results?
- Do I need to do anything to care for myself after the procedure?
Your GP, obstetrician or midwife can answer your questions and give you more information on CVS. They may also refer you to a genetic counsellor who can guide you through the implications of your results, any decisions you may need to make and the relevant support available. You might find it helpful to talk through how you may feel when you get your results, and what it might mean for you and your family if you have a child with a genetic disorder.
Speak to a maternal child health nurse
Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.
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Last reviewed: March 2022